Such a class-forming coupling device is known from U.S. Pat. No. 4,799,463. In this device for coupling valve activating levers, the hollow shaft has an intermediate wall in the longitudinal direction, so that two channels are formed in the hollow shaft. One channel is designed for feeding oil that lubricates the bearing of the valve activating lever from the internal combustion engine. This oil supply is optionally also provided for supplying hydraulic valve clearance compensating elements with oil. The second channel is used for controlling the coupling pin between the valve activating levers.
It is easy to see that such a hollow shaft is expensive and complicated in production. Furthermore, this configuration has the effect that only a greater number of coupling pins between several valve activating levers can be simultaneously controlled by an electromagnetically activated valve, because otherwise separating walls extending only perpendicular to the longitudinal axis must be installed or a multiple sub-division must be performed.
U.S. Pat. No. 5,476,075 (equivalent to DE 43 31 504) describes a hollow shaft that has several longitudinal channels and also specifies a method for producing such a hollow shaft.
If the coupling pins are activated, e.g., on both sides by pressurized fluid, then two channels in the hollow shaft are not sufficient.
Japanese Patent Application 2005 180 195 A describes a hollow shaft for supporting valve activating levers, with four longitudinal channels in the hollow shaft.